­The 85-year-old is due to step down on February 28. The Pope said he is “fully aware of the gravity of this gesture” but that he lacks the strength to govern Church due to age, according to Vatican's spokesperson Federico Lombardi.

In a statement released by the Catholic Church, Benedict VXI said that “after having repeatedly examined my conscience before God, I have come to the certainty that my strengths, due to an advanced age, are no longer suited to an adequate exercise of the Petrine ministry.”

A Vatican official says they expect the period between Benedict's resignation and the election of a successor to be “as brief as possible,” according to Reuters news agency. However, his resignation means that the Papacy will be vacant until a successor is chosen.

A Vatican spokesman said that the Pope "took us by surprise", suggesting that even his closest aides had not previously been informed of the decision. One said that he was left "incredulous" by the Pope's news. However, the Pope's brother, Georg Ratzinger, said that Benedict had been encountering increasing difficulty walking, and his resignation was part of a "natural process," meaning he had been contemplating stepping down for months. The Pope may want to avoid an exhausting rush of Easter engagements by resigning early in the year.

A conclave of cardinals will meet in March 2013, to elect a new pope after his departure.The Pope will not participate in the election of his successor.

In 2010, the 265th Pope said that he would not hesitate to become the first pontiff to retire willingly from his position in more than 700 years, if he felt unable, “physically, psychologically and spiritually” to run the Catholic Church any longer.

Georg Ratzinger said that the Pope's doctor had recently told him not to make transatlantic trips for health reasons. However, his resignation is not due to any specific illness, according to a spokesperson. Following his departure, he will voyage to a Papal summer residence near Rome, and will then move in to a cloistered residence in the Vatican.

The last time a pope resigned was in 1415.Back then Pope Gregory XII pronounced the resignation, which the cardinals accepted. However, the last time a Pope resigned voluntarily, was Celestine V in 1294.

Pope Benedict XVI has been in office since19 April 2005, meaning that he was elected at the age of 78.

Since his assumption of the title, he has been embroiled in the ‘Vatileaks’ scandal, in which his former butler was accused of stealing confidential information, and leaking it to journalists. The leaked data, which surfaced in January 2012, contained detailed exposes of the institution, revealing the power struggles, factional fighting and personal finances of the Papacy.

The reports also described competing churchmen initiating homosexual smear campaigns against each other and revealed a number of blocked reforms geared towards the transformation of the Vatican Bank – an institution already infamous for its lack of transparency.

Pope Benedict XVI posts his first tweet using an iPad tablet after his Wednesday general audience in Paul VI's Hall at the Vatican December 12, 2012 (Reuters / Giampiero Sposito)

The Pope emerged from the scandal as frail, indecisive, and remote, and concerned only with the spiritual side of affairs while blind to earthly misdemeanors around him. Cardinal Tarcisio Bertone – the Vatican’s administrative head – emerged as a figure gaining increasing power as Benedict’s health weakened.

“In the last few months there was much talk about wars inside the Vatican about the future. They said that the Secretary of State Bertone was going to step down, but he did not. The pope did! This was the biggest surprise. Everybody was expecting for some of the administration, of the government, let’s say, of the church, to be changed… Nobody expected the pope to step down,” journalist Franco Oliva told RT.

Paolo Gabriele, the butler involved, said that he "was sure that a shock, perhaps by using the media, could be a healthy thing to bring the Church back on the right track," going on to explain his feelings that the pope was not adequately informed of problems the letters outlined.

Benedict has reportedly been critical of his predecessor, John Paul II, for remaining in the position as he became too old and incapable to fully cope with its demands.

Israel’s chief Rabbi has praised the Pope's inter-religious outreach, and has wished him good health, according to a spokesman. Italian Prime Minister Mario Monti, has also said, "I'm greatly shaken by this unexpected news," according to the Italian newspaper La Stampa's website.

The German chancellor, Angela Merkel, also responded to the new, on account of the Pope’s German roots. She said that if the Pope feels he is too weak to carry out his duties, his wishes "must be respected."

Benedict is the sixth German to serve as Pope, and the first since the 11th century.

The Pope was enlisted in Germany's Hitler Youth at the age of 14, as required by the state, and was briefly held as a prisoner-of-war by the Allies in 1945.

Papal controversy erupted in 2009, when he lifted the excommunication of four bishops of the Society of Saint Pius X. One was a Holocaust-denier, Richard Williamson, from Britain.

The Vatican said Benedict had been unaware of Williamson's views when he acted.

Pope Benedict XVI sits during a mass in Santiago de Cuba on March 26, 2012 (AFP Photo / Osservatore Romano)

­

Pope of the digital age

­Elected on this post in 2005 upon the death of Pope John Paul II, 78-year-old former Cardinal Joseph Ratzinger became one of the oldest new popes in history.

Born in 1927, in Bavaria, he was the son of a police officer. Joseph Ratzinger was ordained in 1951, at age 24.

Pope Benedict XVI is seen as a religious conservative in line with his predecessor’s policies.

During his Papacy, Benedict XVI was actively involved in social media. He is online everywhere these days — from tweets on his @Pontifex account to daily YouTube videos to a new app dubbed 'The Pope App', launched just recently.

The five-star application received extremely positive reviews from those who downloaded it.

Pope Benedict XVI entered history as the first head of the Roman Catholic Church to join the Twitter microblogging website in December 2012.

We must trust in the mighty power of God’s mercy. We are all sinners, but His grace transforms us and makes us new.

World’s oldest electoral tradition

­Popes are elected by a conclave of the entire body of Catholic cardinals. Since 1274 the officials are sequestered and not permitted to leave until the new Pope is elected, a rule aimed at preventing the Holy See from being left unoccupied for a long period of time. Papal conclaves are now held in the Sistine Chapel.

A candidate must be under 80 years old on the day the Holy See becomes vacant and must win the support of two-thirds of the College of Cardinals, consisting of up to 120 clergymen. Dozens of ballots may be cast over the day, if the electors cannot come to an agreement.

The results of election rounds held on a given day are announced to the people assembled in St. Peter’s Square, when the ballots are burned. Black smoke indicates that the election failed to produce a result, while white smoke signals that a new pope has been chosen.

It is customary for a pope to select a new name. The tradition stretches back to the time before succession of the Holy See was institutionalized. Pope John II, who became the leader of the Catholic Church in 533, felt that his given name Mercurius, honoring the Roman god, was inappropriate for his position, so he had it changed.

The procedure for selection of a new Pope was first formalized in 1059, which makes it the oldest method of choosing a leader of an institution still in use. The rules evolved, however, with details refined over the centuries.